Collection apparatus for rinsing media of an atomizer

ABSTRACT

The disclosure relates to a collecting device for collecting fluid media (e.g. rinsing agent, paint residues), which are produced when rinsing an atomizer (e.g. rotary atomizer) in a painting plant. The collecting device according to the disclosure comprises a collecting container with an insertion opening at the top of the collecting container for inserting the atomizer into the collecting container. Furthermore, the collecting device according to the disclosure comprises a lateral container wall which externally delimits the collecting container and is substantially impermeable to paint in order to prevent paint from escaping from the collecting container. The disclosure provides that the lateral container wall of the collecting container is at least partially air-permeable so that moist air can escape from the interior of the collecting container to the outside.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage of, and claims priority to, PatentCooperation Treaty Application No. PCT/EP2019/083282, filed on Dec. 2,2019, which application claims priority to German Application No. 102018 130 809.4, filed on Dec. 4, 2018, which applications are herebyincorporated herein by reference in their entireties.

FIELD

The disclosure relates to a collecting device for collecting fluid media(e.g. rinsing agent, paint residues), which accumulate during cleaning(e.g. short rinsing, color change rinsing) of an atomizer (e.g. rotaryatomizer) in a painting plant. Furthermore, the disclosure comprises acorresponding operating method.

BACKGROUND

In modern painting plants for the painting of motor vehicle bodycomponents, rotary atomizers are usually used for paint application,which emit a spray jet of the paint to be applied. During a color changeand during interruptions of operation, for example during the night orduring the weekend, these rotary atomizers are rinsed inside and cleanedoutside to avoid paint deposits and contamination by residual paint. Theinternal channels of the rotary atomizer are usually rinsed with arinsing agent to remove the paint remaining in the rotary atomizer. Inthe past, these rinsing processes of the rotary atomizers went into theso-called wet scrubbing under the painting booth. However, since theintroduction of dry rinsing, this is no longer possible, so thatseparate collecting devices (e.g. hoppers) are used for this purpose. Insome cases, devices that are used for external cleaning of the atomizerand are described in EP 1 367 302 A2, for example, are used to collectthe media of the rinsing processes. For a cleaning or rinsing process,the rotary atomizer to be cleaned is introduced into the cleaning deviceby a painting robot and then cleaned in the cleaning device.

This well-known technology, e.g. with hoppers for collecting the rinsingmedia, is however associated with various disadvantages. Iftwo-component material (2K material) is flushed from the atomizer intothe hopper, it must be prevented from hardening in the hopper. To dothis, the hopper must be supplied with solvent (for example a thinner),which is expensive in terms of energy. In addition, the subsequenttreatment of the residues of paint and solvent also generates highcosts. In order to keep energy consumption low, the solvent is clockedfrom the paint mixing chamber to keep the hoppers free, which requirescomplex communication with the robot controller. Furthermore, there is arisk of clogging of the hoppers, for example by too much lubricant,cloths, rags, waste, etc. Finally, the well-known cleaning devices inthe paint booth lead to emissions of volatile organic compounds (VOC).

If the rinsing processes are carried out in a cleaning device forcleaning the outer surface of the atomizer, there is a risk that movingparts or components with openings (e.g. nozzles) may become clogged whenrinsing 2-component material and the cleaning function of the device isno longer given.

For the state of the art, reference is also made to US 2012/0042912 A1.

Finally, EP 1 346 777 A1 discloses a measuring device that is designedaccording to the preamble of claim 1 and also allows for the cleaning ofan atomizer. An outlet is arranged on the underside of the collectingcontainer, which is closed by a flap during a cleaning process and isopened after a cleaning process so that coating agent residues canescape into the outlet. A disadvantage here is the fact that the outletpipe must be flushed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a perspective view of a collecting device according to thedisclosure from an inclined position,

FIG. 2 a perspective view of the collecting device in FIG. 1 from anoblique angle from below, and

FIG. 3 is a perspective section of the fall-arrest device from FIGS. 1and 2.

DETAILED DESCRIPTION

The disclosure is based on the technical-physical discovery that withthe known cleaning devices and collecting devices, moist, turbulent airis generated inside the collecting device during the rinsing process,which can settle on the atomizer housing in the form of moisture.However, this moisture on the atomizer housing leads to increasedsoiling of the outer shell of the atomizer during painting. In addition,the moisture on the outer shell of the atomizer can cause high-voltageinterference with the electrostatic charging of the coating material.Finally, the moisture on the outer shell of the atomizer can also leadto defect patterns on the painted surface. The disclosure therefore alsoaims at preventing this moist, turbulent air in the collecting device.

The collecting device according to the disclosure first of all has, inaccordance with the collecting devices (e.g. hopper) described above, alargely closed collecting container which preferably has an insertionopening on its upper side through which the atomizer can be insertedinto the collecting container for a rinsing process. The lateralcontainer wall of the collecting container limits the collectingcontainer to the outside and is essentially impermeable to paint inorder to prevent paint from escaping from the collecting containerduring a rinsing process.

The collecting device according to the disclosure differs from the knowncollecting device described above (e.g. with a hopper) in that thelateral container wall of the collecting container is at least partiallypermeable to air so that moist air can escape from the interior of thecollecting container to the outside. This advantageously preventsmoisture from settling on the outer shell of the atomizer to be cleanedduring a rinsing process, since such moisture is associated with theproblems described above.

In a preferred embodiment of the disclosure, the air permeability of thecontainer wall is achieved by numerous air outlet openings in thecontainer wall so that the moist air from the interior of the collectingcontainer can escape to the outside through the air outlet openings.

For example, the number of air outlet openings can be larger than 10, 20or 50 to achieve sufficient air permeability.

Preferably, the total cross-section of the air outlet openings is atleast 5%, 10%, 20%, 30%, 40%, 50%, 60% or 70% of the total wall area ofthe container wall to achieve sufficient air permeability of thecontainer wall.

An advantage of the collecting container is that it has no media supplylines, which means that no software control is necessary andretrofitting can be carried out without additional valves or tubing.

In a preferred embodiment of the disclosure, the cross-section of theindividual air outlet openings is not uniform, i.e. the individual airoutlet openings have different cross-sections. Preferably, thecross-section of the air outlet openings is largest near the insertionopening of the collecting container (i.e. at the top) and then decreasesin one or more steps in the direction of insertion (i.e. downwards) toreach a minimum in the central area. The cross-section of the air outletopenings then increases again towards the bottom of the collectingcontainer, preferably in a single step. The air outlet openings can thushave, for example, four different cross-sections. It should be mentionedhere that the cross-section of the individual air outlet openingspreferably only varies along the direction of insertion, whereas thecross-section of the individual air outlet openings in thecircumferential direction of the collecting container is preferablyuniform.

It should also be mentioned that the air outlet openings form a certainflow resistance and thereby reduce the outlet velocity of the airflowing out through the air outlet opening. This is particularlyadvantageous if the container wall has a flat paint filter which retainsthe paint in the paint filter and thus prevents the paint from escapingfrom the collecting container to the outside. The outlet velocity of theair flowing out of the collecting container through the air outletopenings is therefore preferably less than 5 m/s, 4 m/s, 3 m/s, 2 m/s oreven less than 1 m/s. In the preferred embodiment of the disclosure, theoutlet velocity of the outflowing air is in the range of 0.05 m/s to 2m/s, whereby a value of essentially 0.5 m/s has proven to beadvantageous.

It has already been briefly mentioned above that the container wallusually has a flat paint filter in order to prevent paint from escapingfrom the interior of the collecting container to the outside despite theair permeability of the container wall. Preferably, this paint filter islocated on the inside of the container wall, however, it is alsopossible that the paint filter is located on the outside of thecontainer wall.

In the preferred embodiment of the disclosure, the paint filter is afilter mat covering the container wall, whereby such filter mats areknown per se from the state of the art and therefore need not bedescribed in detail.

However, it should be mentioned that the paint filter (e.g. filter mats)should cover the air outlet openings completely in order to avoid adisturbing paint leakage.

It should also be mentioned that the paint filter (e.g. filter mats) ispreferably replaceable. This makes sense because the paint filterbecomes increasingly clogged with the collected paint during operation,so that the paint filter (e.g. filter mats) should be replaced in goodtime before it becomes completely clogged.

It should also be mentioned that the paint filter can absorb the paintwith a certain quantitative absorption capacity, i.e. the paint filtercan absorb a certain amount of paint until the paint filter is clogged.Preferably, this quantitative absorption capacity of the paint filter ismuch greater than the amount of paint produced during a rinsing process,in particular by a factor of 2, 3, 4, 5, 10, 20 or 50 to over 1000. Thisis useful so that the paint filter does not have to be replaced often.

It should also be mentioned that the paint filter (e.g. filter mats)preferably extends over the entire lateral and lower container wall.

According to the disclosure, the collecting container has an outletwhich is preferably located at the bottom of the collecting containerand serves to drain off paint residues and/or rinsing agent.

Since the majority of the paint is collected in the paint filter (e.g.filter mats), only very strongly diluted paint material passes throughthe outlet into the return system. This has the advantage that therecirculation does not have to be flushed, as the paint material is sodiluted that it does not stick in the pipes. This saves a great deal ofenergy and material for the supply and preparation of diluent.

It should also be mentioned that the usual rotary atomizers usually havea negative pressure area in the area between the rotating bell plate andthe shaping air ring. During a rinsing process, this negative pressurearea can cause moist air to be drawn out of the collecting container andonto the atomizer surface, which is undesirable. The atomizer to beflushed is therefore preferably introduced into the collecting containerso far that the negative pressure area of the atomizer is within thecollecting container during a cleaning process. This prevents thenegative pressure area between the bell plate and the shaping air ringfrom causing moist air to escape from the collecting container. Thecollecting container should therefore preferably have a sufficientimmersion depth to allow the atomizer to be flushed in.

Because of the negative pressure area between the rotating bell plateand the shaping air ring of the rotary atomizer described above, itshould also be possible for ambient air to flow into the collectingcontainer during a flushing process. The inlet opening of the collectingcontainer is therefore preferably considerably larger than the outerdiameter of the atomizer housing (“tube”) at the front end so thatambient air can flow into the collecting container through the annulargap remaining between them. The inside diameter of the inlet opening ofthe collecting container is therefore preferably larger than 150%, 200%,250% or 300% of the frontal outside diameter of the atomizer housing.

It should also be mentioned that the collecting container should have asufficiently large internal volume. Thus, a certain amount of air isproduced during a flushing process, as, for example, air is releasedfrom the atomizer's shaping air nozzles. The internal volume of thecollecting container should therefore be at least one third and/or atmost twice the amount of cleaning air produced during a cleaningprocess. In the preferred embodiment of the disclosure, the internalvolume of the collecting container is substantially two-thirds of theamount of air generated during a single flushing operation. In case ofdifferent possible flushing processes with different parameters, thisadjustment is preferably made with respect to the flushing process withthe largest air volume.

It should also be mentioned that the diameter and the height of thecollecting container according to the disclosure are preferablyessentially the same.

During operation, the collecting container is usually closed at its topby a cover, with the insertion opening located in the cover. This covercan be either flat, concave or convex when viewed from the outside andis designed to prevent VOCs from escaping from the collecting container.

However, the disclosure does not only claim protection for thecollecting device described above. Rather, the disclosure also claimsprotection for a corresponding operating method. The details of theoperating method according to the disclosure are essentially alreadyapparent from the above description of the collecting device accordingto the disclosure, so that a complete separate description of theoperating method according to the disclosure is not necessary.

However, it should be mentioned that there is a risk of sparking duringoperation of an atomizer with an electrostatic coating charging. Theatomizer to be flushed with the electrostatic coating agent charging maytherefore only be introduced into the collecting container when theelectrostatic coating agent charging is switched off, i.e. when theatomizer is de-energized. It should be mentioned here that the atomizeris usually introduced into the collecting container by a painting robot,whereby the painting robot is controlled by a robot control. Thedisclosure now preferably provides that the robot control defines arestricted area around the collecting container when the coating agentcharge is switched on, so that the atomizer cannot be introduced intothe collecting container when the coating agent charge is switched on,in order to avoid a sparkover.

The disclosure is particularly advantageous for the collection of theflushing media of atomizers (e.g. rotation atomizers) that applytwo-component paints. However, the disclosure is also suitable forcollecting the rinsing media of atomizers that apply one-componentpaints.

In the following, a preferred embodiment of a collecting deviceaccording to the disclosure is described, as shown in FIGS. 1 to 3.

The collecting device according to the disclosure serves to collect therinsing media of a rotary atomizer used in a painting plant for paintingbody parts of motor vehicles. The collecting device according to thedisclosure is therefore preferably arranged inside a painting booth,e.g. on the floor of the painting booth, preferably at floor level.

The collecting device initially has a pot-shaped collecting container 1,which is cylindrically shaped. The collecting container 1 is limited onthe outside by a container wall 2, which is impermeable to paint and airand is usually made of steel. However, in the container wall 2 of thecollecting container 1 there are numerous air outlet openings 3-6 toallow moist air to escape from the inside of the collecting container 1to the outside, as described in detail below.

The collecting container 1 is closed on its upper side with a cover 7,whereby in the cover 7 there is an insertion opening 8 for the insertionof a rotary atomizer. In this embodiment, the cover 7 is concave at theperipheral edge of the insertion opening 8 when viewed from outside, asshown in FIG. 3. Alternatively, it is also possible that the cover 7 isconvex or flat when viewed from the outside.

The collecting container 1 has an outlet 9 on its underside, which isconnected to a return line in order to be able to drain paint andsolvent residues into the return line.

On the inside of the container wall 2, the container wall 2 is coveredwith filter mats 10 which prevent paint from the inside of thecollecting container 1 from escaping to the outside through the airoutlet openings 3-6. The filter mats 10 therefore collect a large partof the paint produced during operation. This is also advantageousbecause only small residual quantities of paint have to be removedthrough the outlet 9, so that the recirculation does not have to beflushed, since the paint material is diluted in the recirculation sothat it does not stick in the pipes. This saves enormous amounts ofenergy and material for the supply and preparation of paint thinner.

It should also be mentioned that the cross-section of the individual airoutlets 3-6 is not uniformly constant. Rather, the cross-section of theindividual air outlets 3-6 varies along the direction of insertion,which is shown in FIG. 3 by a double arrow. For example, the air outlets3 at the top of the collecting container 1 have the largestcross-section. The cross section of the air outlet openings 4 followingalong the direction of insertion is then still approximately half aslarge. The following air outlet openings 5 then have a cross sectionwhich corresponds to only about a quarter of the cross section of theair outlet openings 4. Along the direction of insertion, the air outlets6 follow, which again have a larger cross section that is approximatelytwice as large as the cross section of the air outlets 5. The crosssection of the air outlets 3-6 decreases in the direction of insertionstarting from the insertion opening 8 and then reaches a minimum at theair outlets 5, only to increase again. This design of the cross-sectionof the air outlets 3-6 has proven to be advantageous during operationfor reasons of flow dynamics.

It should also be mentioned that the filter mats 10 completely cover thecontainer wall in the area of the air outlet openings 3-6 to preventpaint from escaping. In addition, the filter mats 10 preferably alsocover the bottom of the collecting container 1, so that paint can onlyenter the outlet 9 after passing the filter mats 10.

1.-17. (canceled)
 18. A collecting device for collecting fluid mediawhich arise when rinsing an atomizer in a painting installation, with a)a collecting container, b) an insertion opening, in particular at thetop of the collecting container, for inserting the atomizer into thecollecting container, and c) a lateral container wall which externallybounds the collecting container and is substantially impermeable topaint in order to prevent paint from escaping from the collectingcontainer, the lateral container wall of the collecting container beingat least partially permeable to air in order to allow moist air toescape from the interior of the collecting container to the outside, d)an outlet to drain at least one of the paint and rinsing agent from thecollecting container, and e) a paint filter in the container walladapted for retaining the paint and thereby preventing the paint fromescaping from the collecting container to the outside, f) wherein thepaint filter is also arranged in the flow path into the outlet, so thatthe paint filter must be passed when flowing into the outlet.
 19. Acollecting device according to claim 18, wherein the lateral containerwall of the collecting container has numerous air outlet openings,wherein the moist air can escape from the interior of the collectingcontainer to the outside through the air outlet openings.
 20. Acollecting device according to claim 19, wherein a) the air outletopenings together have a certain total cross-section, b) the containerwall has a certain wall area, c) the total cross-section of the airoutlet openings is at least 5% of the total wall area of the containerwall.
 21. A collecting device according to claim 19, wherein a) thecross-section of the individual air outlet openings varies along thedirection of insertion, in particular from a large cross-section nearthe insertion opening via a minimum cross-section in the central area toa larger cross-section near the bottom.
 22. A collecting deviceaccording to claim 19, wherein the cross-section of the individual airoutlet openings is uniform in the circumferential direction.
 23. Acollecting device according to claim 19, wherein a) the air outletopenings form a certain flow resistance and thereby reduce the outletvelocity of the air flowing out through the air outlet openings, and b)the outlet velocity of the air flowing out of the collecting containerthrough the air outlet openings is less than 5 m/s.
 24. A collectingdevice according to claim 18, wherein the paint filter is flat.
 25. Acollecting device according to claim 24, wherein the flat paint filteris arranged on the inside of the container wall.
 26. A collecting deviceaccording to claim 25, wherein the paint filter has at least one filtermat which covers the container wall, in particular on the inside of thecontainer wall.
 27. A collecting device according to claim 24, whereinthe paint filter completely covers the air outlet openings.
 28. Acollecting device according to claim 24, wherein the paint filter isreplaceable.
 29. A collecting device according to claim 24, wherein thepaint filter can absorb the paint with a certain quantitative absorptioncapacity, the quantitative absorption capacity of the paint filter beinggreater than the paint quantity produced during a rinsing process.
 30. Acollecting device according to claim 24, wherein the paint filterextends over the entire lateral and lower container wall.
 31. Acollecting device according to claim 18, wherein a) the collectingcontainer has a certain maximum immersion depth up to which the atomizercan be introduced into the collecting container through the insertionopening, b) the atomizer has a negative pressure area between the bellplate and the shaping air ring, and c) the maximum immersion depth issuch that the negative pressure area of the atomizer is inside thecollecting container during a rinsing process.
 32. A collecting deviceaccording to claim 18, wherein a) the insertion opening of thecollecting container has a certain inner diameter, b) the atomizer hasan atomizer housing with a certain front-side outer diameter, c) theinner diameter of the insertion opening of the collecting container islarger than the front-side outer diameter of the atomizer housing, sothat ambient air can flow from outside into the collecting container tothe negative pressure area, and d) the inner diameter of the insertionopening of the collecting container is larger than 150% of the frontalouter diameter of the atomizer housing.
 33. A collecting deviceaccording to claim 18, wherein a) a certain amount of purge air isproduced during a rinsing process, in particular from shaping airnozzles of the atomizer and from incoming ambient air, b) the collectingcontainer has a certain internal volume, c) the internal volume of thecollecting container is at least ⅓ the amount of purge air.
 34. Acollecting device according to claim 18, wherein the collectingcontainer has a certain diameter and a certain height, wherein thediameter is substantially equal to the height.
 35. A collecting deviceaccording to claim 18, wherein the collecting container is closed at itstop by a cover which is flat, concave or convex in shape when viewedfrom the outside.
 36. A collecting device according to claim 35, whereinthe cover is flat in shape when viewed from the outside.
 37. Acollecting device according to claim 35, wherein the cover is concave inshape when viewed from the outside.
 38. A collecting device according toclaim 35, wherein the cover is convex in shape when viewed from theoutside.